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site should be greater than six square root of the
number of all the grid sites. We denote the num-
ber of all the grid sites by N , and the minimal
number of neighbors should be greater than or
equal to N
Besides, the average utilization, the maximum
utilization and the minimum utilization of resource
i of site s are defined by U_AVG i ( s ), U_MAX i ( s )
and U_MIN i ( s ) respectively. Therefore, the RL of
site s is defined as
6 . Therefore, each grid site maintains
at least 6 neighbors to ensure the network
connectivity. In addition, in order to improve the
load balancing, SALB estimates the remaining
resources capability of each neighbor site and
selects the neighbors with more remaining capa-
bilities for migrating jobs. Suppose that a grid site
has m kinds of resources, and each resource's
remaining capability of site s is denoted by RC i ( s ),
where i = 1 … m . The weight of each resource is
denoted by W i ( s ). Assume that DRC ( l , r ) is the
difference of remaining capability between the
local site l and the remote site r . Then,
U U AVG s
U MAX s
_
( )
m
RL s
=
W s
i
i
( )
( )
( )
i
_
( )
U MIN s
_
=
i
i
i
i
(2)
while the AL of site s is defined as
m
1
AL s
=
W s U s
i
( )
( )
( )
(3)
i
i
=
Moreover, SALB predefines the high threshold
of RL by RL_H , the low threshold of RL by RL_L ,
the high threshold of AL by AL_H , and the low
threshold of AL by AL_L . The status of different
combinations of RL and AL are described as fol-
lows: When RL is greater than or equal to RL_H ,
the status is set to be “High”. When RL is less than
RL_H and is greater than RL_L , the status is set
to be “Moderate”. When RL is less than or equal
to RL_L , the status is set to be “Low”. When AL
is greater than or equal to AL_H , the status is set
to be “High”. When AL is less than AL_H and is
greater than AL_L , the status is set to be “Moder-
ate”. When AL is less than or equal to AL_L , the
status is set to be “Low”. The statuses of different
combinations of RL and AL are shown in table 1.
According to the statuses of RL and AL , we
classify the status of local sites to be “Sendable”
RC l
RCi rii
( )
( )
m
1
DRC l r
( , )
=
W l
( )
i
(1)
i
i
=
When a gird site joins the P2P Grid system, it
randomly selects 2 6 sites as the candidates of
neighbors and picks the first 6 sites with the
smaller DRC as its neighbors. Thus, these neigh-
bors have more remaining resources capability
for load balancing. To avoid the out-of-date in-
formation, we also set a time interval t for each
grid site to re-select neighbor sites periodicity. In
addition, SALB estimates the relative loading
( RL ) and the absolute loading ( AL ) of grid sites
to determine whether the local site is sendable
and which neighbor sites are receivable. We define
the utilization of resource i in site s by U i ( s ).
Table 1. States of RL and AL
RL status
AL status
RL RL_H
High
AL AL_H
High
RL_H > RL > RL_L
Moderate
AL_H > AL > AL_L
Moderate
RL RL_L
Low
AL AL_L
Low
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